Adafruit Industries, Unique fun DIY electronics and kits. PRODUCT ID 3. 59. This breakout is chock full o sensors Add basic gesture sensing, RGB color sensing, proximity sensing, or ambient light sensing to your project. This breakout is chock full o sensors Add basic gesture sensing, RGB color sensing, proximity sensing, or ambient light sensing to your project with the  Adafruit APDS9. Proximity, Light, RGB and Gesture Sensor. When connected to your microcontroller running our library code it can detect simple gestures left to right, right to left, up to down, down to up are currently supported, return the amount of red, blue, green, and. RCA AR 8. 8 Series Receivers. High B on filter capacitors and audio output transformer when the. TRANS position This is because the FUNCTION switch. B at the output of the triple filter of the power supply. The audio transformer is connected at the second filter capacitor and. Reducing the load on the B while in Stand By causes the voltage. Although there are bleeder resistors in the circuit their load. K A B resistors have drifted quite high in value so they no longer. Some. overseas users. B excursion is high enough to cause problems in the. I tested my original CR 9. GS00480-04-SD_FXA.jpg' alt='Serial Number Rotary Watch Bands' title='Serial Number Rotary Watch Bands' />After months of leaks and hints, Fibit has finally revealed its newest wrist wearable The 300 Fitbit Ionic. Fitbit claims up to four days of battery life, a refined. The Texarkana Gazette is the premier source for local news and sports in Texarkana and the surrounding Arklatex areas. This was asked a number of years ago but is still valid. The reason the rotary does not work on the Mega2560 is due to the differences in interrupts between the Uno. Serial Number Rotary Watch Bands' title='Serial Number Rotary Watch Bands' />B. REC MOD and measured 4. TRANS our AC line is 1. This is about 1. 00vdc of head room and should not cause any. It might be. possible that the 2. AR 8. 8 on 2. 40vac 5. This may account for. B in some overseas locations where the house voltage. RCA rated the 2. 40vac primary to be able to go up to. Western Wood Products Association, representing Western lumber manufacturers. EHam. net Classifieds Search Results 820 records found. Display All ads. B voltages. Normal setting in the USA would be on. The normal encountered AC voltage in the USA is 1. One note also. switching transients when actively using the TRANS position for. All of that being said, its probably a good idea to avoid. TRANS. position actively as the SENDREC function. Safe operation of the AR 8. TR switch if your primary mode of operation is CW. This would have the. REC. CW position all the time with the TR switch protecting the receiver. Electronic T R switches were designed for break in CW operation. AM operation using an. T R switch isnt really practical because of the audio feedback. Remote muting can easily be accomplished and is detailed in the. Using the AR 8. 8 as a Ham Station Receiver Easy and. Reversible Muting Mod. Audio Output Transformer failure when using speakers other than the. Z ohm speaker This is nonsense. An. important part of the impedance calculation involves frequency. So what. frequency is standard for speaker calculationsWell, actually the. Pretty vague Suffice it to. All of that being said, the manual. Z ohms as the desired speaker nominal impedance. Note that. when operating on Hi Z earphones the phone jack connects a 5 ohm 4 watt. Apparently RCA thought that 5 DC ohms was a close enough match. AF transformer. Using a 4. Z ohm speaker is perfectly. If you can find a 3. Z ohm speaker fairly easy you will find. AF gain control doesnt have to be advanced quite as much as. Z speakers. Although I have operated AR 8. Z speakers and havent had any trouble, I think the 3. Z. speakers work very well with the receivers and are worth looking for. One thing that is important relates to receiver operation exclusively on. Hi Z headphones with no loudspeaker connected, in which case the operator must be sure that the. This is a. two position jack and when the phone plug is all the way in, then. Z ohm output and the phones operate. Half way in was to allow the Hi Z  phones to. Z ohm speaker winding to allow both. NOTE The first 3. AR 8. 8LF receivers have a different audio output transformer that has a. Z and 2. 0 Z ohm outputs. Audio Output. Fixed Bias Operation The cathode of the 6. K6 AF Output tube is. CT of the B winding of the power transformer with resistors. Fixed bias. allows the AR 8. K6 to develop more power with better audio. The other option would have been. This was the economical way to bias an audio amplifier and. However. there are dangers when operating fixed bias. If, for some reason, the. This can rapidly cause damage to the tube and sometimes. Some AR 8. 8 users advocate adding a 1. Theoretically, bias failure is possible. BUT, the resistors used in the bias voltage dividers are high rated. Failure of this circuit is rare. However, if you are a. Most of the time. If a problem. developed it might be several hours before anyone noticed and the. In amateur use today, a. Insufficient BFO. Injection Most versions of the AR 8. BFO into the grid circuit of the 3rd IF. This adds some gain to the BFO at the detector stage and. CW mode. But, along came. SSB which required a higher ratio of BFO injection to the signal level. BFO to substitute for the signals missing carrier and. The normal ham modification approach added a. BFO. injection which seemed to give better results on SSB. However, its much. AVC by switching to MAN, increase the AF gain to maximum and the reduce the RF. Gain to a level where the signal to BFO ratio is correct. SSB. This then allows the receiver to. CW reception. However, listening to a SSB net can. RF gain for each net participant. If you dont do CW, then maybe. BFO injection makes sense. Incidentally, the final versions of. AR 8. 8 series, the CR 8. SC 8. 8 uses a fixed 1. BFO.  5. Remove Negative Feedback for. Audio Improvement This all depends on what. This originally was done by. Today, most vintage receiver users, especially AM hams, would find this. The audio response. AR 8. 8 to provide relatively low. Using a close match to the 2. Z audio output. probably does more to improve the audio than removing the negative. I have a feeling that this modification. When the AR 8. 8 receivers. VERY LOUD. Normal position of the AF GAIN control is about 2. Z speaker. 6. Reduce Value of RF Gain. Control Divider to Improve Sensitivity The RF Gain. K ohm potentiometer connected to the negative bias. RF Gain pot. The low end of the RF Gain pot is connected to chassis through a. K to 6. 8. K in value depending on the. AR 8. 8 receiver. The value of this resistor. RF Gain control and therefore controlled the maximum sensitivity of the. This resistor value was usually set to allow about 2 volts. RF Gain control minimum R of the. Some users feel that a bit more sensitivity can be had by lowering. R to ground and thereby reducing the minimum. Generally, most users feel that around 2. K is a good. value. This will reduce the minimum bias to about 1. Before. changing the value of the resistor be sure to check its actual value as. K to 6. 8. K called out by the receiver design. If. the resistor value is within the proper range and you want to somewhat. K This is an easy. K. The. results are somewhat subjective but its an easy mod to remove if the. Tube Substitutions There is a subtle difference between the metal 6. SA7 used as the mixer. AR 8. 8 and the glass 6. SA7. GT tubes. Some users believe that the. This is easy to try since it is just a. I have only found this substitution in one. Also, substitution of 6. SG7. W tubes for standard 6. SG7 tubes was supposed to improve signal to. Expect results from subtle to no apparent improvement at. What does seem to be important is the quality of tubes used in the. Many users report better performance with all NOS RCA tubes. Certainly, a complete set of NOS JAN tubes will significantly. Miniature Tube Modifications. Spider Man Venom Windows 7. CQ magazine, notorious for publishing articles that advocated the. Worthwhile Improvements for that Old. Receiver by Paul H. Lee, February 1. 95. The article details. CR 8. 8A receiver that involved the replacement of. Most. of the article details replacing the 6. SG7 1st RF amplifier tube with a 6. BK7. A dual triode tube, claiming a. Also, the article continues with the BFO change to a. BE6, acting somewhat like a product detector. Replacement. of the Mixer tube with a 6. BA7 nine pin tube it was the Mixer tube used. Collins 7. 5A 4 so. Additionally, all of the remaining 6. SG7. tubes were replaced with 6. BA6 tubes. The article concludes with the. Venezuela was now installing CR 8. As that. incorporated. RF modification. The article is reminiscent of post L.